In the field of cryptography, a key stream is a stream of characters that are combined with a plain text message to produce an encrypted message, known as the cipher text. The characters that are combined with the plain text message may be random or pseudorandom characters, such as bits, bytes, numbers or actual characters like A-Z depending on the usage case.
The Advanced Encryption Standard (AES) is a block cipher logic specification for the encryption of electronic data established by the U.S. National Institute of Standards and Technology (NIST). Generally, an Advanced Encryption Standard (AES) engine has a long critical path. The critical path may be regarded as the path that takes the longest time in a combinational logic system for information to navigate through. As a result AES engines having longer critical paths cannot be run at a higher clock frequency. Further, AES engines are set to deliver large block size cipher texts, usually set at 128 bits. Therefore, the output from AES engines are of large block sizes with lower frequency.
In some applications, however, there is a requirement for smaller block size cipher texts that are of a higher frequency. Existing solutions do not allow the production of small block size cipher texts at a higher frequency.
This background information is provided to reveal information believed by the applicant to be of possible relevance to the present invention. No admission is necessarily intended, nor should be construed, that any of the preceding information constitutes prior art against the present invention.